Heat exchange apparatus



Feb. 10, 1959 J. l.. MORGAN HEAT EXCHANGE `APF! \.RATUS Filed Oct. 5 1955 @@@QQ @@.Q

UnitedStates Patent() HEAT EXCHANGE APPARATUS Jack L. Morgan, Beloit, Wis., assigner to Yates-American Machine Company, Beloit, Wis., a corporation of Delaware Application October 3, 1955, Serial No. 538,090

3 Claims. ('Cl. 257-236) AThe present invention relates generally to improved heat exchange apparatus and more specifically is directed to the provision of an improved baille plate for use in heat exchangers of conventional design.

Known forms of tubular heat exchange apparatus make use of a plurality of spaced baille plates having a number of apertures extending therethrough which support tubes running longitudinally of the body portion of the heat exchange unit. The baille plates are of substantially circular design having a segment removed along one side thereof to promote the tortuous passage of fluid through the body portion of the heat exchanger in contact with the outer surfaces of the tubes maintained therein. The apertures in the baille plates are of a greater diameter than the outer diameter of the tubes to allow ready insertion `of the tubes therethrough. The sharp edges of the baille plates are apt to, and often do, cut into the tubes as a result of vibration set up upon the operation of the unit. In properly positioning the baille plates in spaced relation within the body portion of the heat exchanger, it is necessary to utilize rods which support sleeve spacers intermediate each baille plate to eliminate longitudinal movement of the plates along the tubes.

The main difficulty confronting ecient operation of a heat exchange unit f conventional design is the occurrence of a high percentage of leakage through the baille plates either in the areas of the tube apertures or about the outer peripheries thereof. The presence of this type of leakage reduces the amount of iluid which is ilowed through the body portion of the heat exchanger in serpentine fashion. The amount of lluid ilowing through the body portion in straight-line ilow is greatly increased and as a result, the heat exchange efciency of the unit is reduced, This particular problem is exceedingly serious as it is generally considered that the attainment of 60 percent proper flow in existing heat exchangers approaches maximum efficiency. In some of the larger units proper llow has been measured as low as 12 percent of the total throughilow and from this it can be readily seen that the presence of leakage about the baille plates materially reduces the efliciency of the heat exchanger. This problem along with the detrimental action of the sharp edges of the baille plate tube apertures resulting in damage to the tubes in response to vibrating forces are the principal problems existing in the field of heat exchange unit design.

It is an object of the present invention to increase the heat exchange eiiiciency of known types of heat exchange units by the provision of a new and improved baille plate for use therein. y

` Another object is to provide a new and improved'baflle plate for use in known types of heat exchange units which is capable of securely receiving the tubes therethrough and protect the tubes from damage resulting from the presence of vibration.

Still another object is the provision of a new and improved baille plate for use in heat exchange units which is provided with anged tube apertures and a partially ice flanged outer periphery capable of substantially reducing leakage, protecting tubes passed therethrough from damage due to vibration and eliminating the necessity of using tie rods and spacers to maintain proper positioning of a plurality of baille plates within the body portion of the heat exchange unit.

Other objects not specifically set `forth will become apparent from the following detailed description made in conjunction with the accompanying drawing, wherein:

Fig. 1 is a perspective view in partial section of a conventional form of heat exchange unit utilizing the improved baflle plates of the present invention;

Fig. 2 is a fragmentary perspective view of the baille plates illustrating the manner in which tubes are mounted thereby;

Fig. 3 is an elevation of an improved baille plate; and,

Fig. 4 is a Asectional view of the baille plate ofFig. 3 taken along line 4 4 therein.

Referring in particular to Fig. 1, a heat exchange unit 10 is shown therein as comprising bonnets 11 and 12 on either ends thereof, eachf having iluid conduit means 13 (one of which is shown) associated therewith. The bonnet 11 is attached to a header plate 14 by bolts 15. The header plate 14 includes an integral body section 16 which telescopically receives one end of an elongated body portion 17. The body section 16 is further provided with a iluid conduit means 1S which allows for the passage of fluid into or out of the body portion 17. The remaining bonnet 12 is similarly attached by bolts 19 to a header plate 20 which has an integral body section 21 telescopically receiving the other end of the main body portion 17. 'Ille body section 21 is also provided with a fluid conduit means similar to that designated by the numeral 18. p Y

Internally of the body portion 17 are a plurality of longitudinally extending, laterally spaced tubes 23 which have their endsv expanded and Arolled in the form of ilanges 24 about the outer edges of apertures within the header plates 14 and 20. Supporting the tubes 23 and controlling the ilow of lluid directed through the conduit means 18 and 22 are spaced baille plates 25 which, as shown in Figs. 2 and 3, may be held in spaced relation by a rod 26 carrying a plurality of sleeve spacers 27. The baille plates 25 are drawn into intimate contact with the ends of the spacers 27 on each of the rods 26 by reason of a nut 2S. This particular arrangement is of conventional design. The baille plates 25 are provided with apertures 29 to receive the rods 26 therethrough. When these rods are used, the receiving apertures 29 are prefer ably of a smaller inner diameter than the outer diameter of the sleeve spacers 27 to allow the latter to abut against the plates 25 and be drawn in close contact therewith by the nuts 28 to prevent leakage through the apertures 29.

The improved bafe plate 25 of the present invention is shown in detail lin Figs. 3 and 4. These plates are each formed with a flat edge 30 which are alternately spaced, as shown in Figs. 1 and 2, to allow fluid to flow through the body portion 17 in contact with the tubes 23 in a serpentine fashion. The remaining outline of the baille plates 25 is semi-circular as indicated by the edge 31 and this edge is in sealing engagement withthe inner surface of the body portion 17 in a manner to be described.

The main features of the baille plates 25 include the manner in which the tube apertures are formed. These apertures are defined by radially extending tlanges 32 which are circumferentially continuous and which are conically shaped in outline.y As illustrated in Fig. 4, the smallest inner diameter of the tube ilanges 32 exists near its outermost extremity and this diameter is in-A tended to lbe sulllciently less than the outside diameter of the tube 23 passed therethrough to bring about sealing n; D engagement between the inner' surface of the flange 32 and the outer periphery of the tube 23. In this manner leakage through the tube apertures in the baffle plates 25 is eliminated and the efllciency of the heat exchange unit is greatly increased.

To further aid in cutting down the leakage of fluid through the baille plates 25 a radially directed flange 33 is provided about the outer periphery of the semi-circular portion 31. This flange, as shown in Fig. 4, extends at an angle approximating 45 with respect to the vertical and horizontal planes. The flange 33 is adapted for sealing engagement with the inner surface of the body portion 17 to prevent leakage of fluid in straight flow lines through the baille about itsfperiphery defined by the semicircular portion 31. As can be readily seen, the'flanges 32 which extend substantially axially with respect to the tubes 23 in conjunction with the radially extending flange 33 are capable of substantially increasing the efficiency of a heat exchange unit by materially reducing the amount of leakage occurring therein.

The provision of the flanges 32 and 33 in addition to the aforementioned advantages are of material importance in other respects. By the use of closely spaced tube apertures in the baille plates 25 it is possible to fabricate the baflle plates from lightweight resilient metallic material while relying on the flanges 32 to impart to the material the requisite rigidity necessary to properly maintain the tubesV 23 in their operative positions. In order to insure the maintenance of proper rigidity it has been found preferable to space the apertures from one another at approximately 0.5 of an inch measuring this distance from centers to centers of adjacent apertures. While it is not always possible to accurately space all of the apertures in this manner, it has been found that by spacing the majority of the apertures used in the baffle plates at this distance with respect to adjacent apertures, adequate rigidity may be impartedto a plate of steel or brass having a thickness within the range of approximately .010 to .030 inch. Under these circumstances it can be readily seen that plates of this nature in the absence of the flanges 32 generally exhibit resilient properties.

By following the aforementioned procedure in fabrieating the baille plates 25 the inherent resiliency of the metallic material may be put to important use in materially aiding in reducing leakage. The flanges 32, by reason of their conical shape, resiliently receive the tubes 23 inserted throughv the plate. As a result the inherent flexibility of the metal of the flanges 32 acts to force the inner surface of the flanges into close sealing engagement with the outer surface of the tubes. To further insure proper sealing contact between the flanges 32 and the tubes 23, the opposed surfaces may be soldered or braised in any suitable manner. For example, spaced rings or threads of solder may be providedl about the outer periphery of the tubes 23 prior to their insertion through the baille plates 25. The rings of solder may then be aligned with the inner surface of the flanges 32 and suitable heatV applied thereto in bonding-the opposed surfaces; The assembled tubes and baille plates may then be readily inserted in the body portion of the heat exchange unit.

An additional'important-result arising from the use of resilient engagement between the flanges 32 and the tubes 23 is the elimination of the use of rods 26 and spacers 27. The close sealing fit between the tubes and: their baille plates eliminates the necessity of using the spacers 27 to insure proper spacingl of the baille plates within the body portion 17. This feature, ofcourse, decreases the total cost of'a heat exchange unit while at, the same time the presence` of the bailles 25 materially increases The flange 33, as stated above, is of particular importance in aiding -in the reduction of leakage between the inner surface of the body portion 17 and the outer periphery of the bafhe plate in contact therewith. As the baille plates 2S may be made from resilient metallic material, the flange 33 is inherently resilient and is capable of flexing into tight sealing engagement with the internal surface of the body portion 17. In installing the assembled baille plates and tubes, it is necessary merely to force the baille plates into the interior of the body portion 17 while relying on the inherent resiliency of the material of the plates to cause the flange 33 to maintain itself in tight sealing engagement with the wall of the body portion. As a result, the combined resilient sealing action of the flanges 32 and 33 presents a fluidtight seal and the flow of fluid is controlled lto an extent that a high percentage of fluid flows tortuously through the body portion 17in contact with the outer surfaces of the tubes 23 without any appreciable loss of efliciency due to straight-through flow.

The presence of the radially extending flanges 32 ,presents a substantially smooth internal surfaceof substantial length to the outer periphery of the tubes 23. As a result, any vibration present in the operation of the heat exchange unit is incapable of causing the tubes 23 to be damaged by contact with sharp aperture edges. Still further, the closely maintained contact between the inner surface of the flanges 32 and their respective tubes 23 is suflicient to eliminate relative movement therebetween in response to vibrating forces.

From the foregoing it can be readily seen that by making use of the new and improved baille plates of the present invention in heat exchange units of known design, a saving in cost of construction may be realized due to the elimination of rods and spacers as well as the use of lightweight material from which the baille plates may be constructed. Still further, the baffle plates may be readily mounted on the tubes and the assembled unit installed within a body portion of a heat exchanger in such a manner as to insure increased efliciency of operation by reducing leakage of fluid past the baille plates. Still further, the life of the tubes utilized is increased by the elimination of damage thereto caused by sharp tube aperture edges.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations yshould be imposed as are indicated in the appended claims.

l claim:

l. A heat exchange unit having an outer elongated shell provided with header plates having first fluid conduit means associated therewith, a plurality of tubes within said shell and extending longitudinally thereof with their ends sealed within apertures in said header plates, said tubes being in communication with said first conduit means, a plurality of spaced baille plates of lightweight resilient metallic material mounted on said tubes within said shell, each of said baille plates including a plurality of apertures extending therethrough each being defined by a circumferentially continuous flange extending axially with respect to said tubes, said flanges being closely spaced to impart rigidity to the main portion of their associated baille plates, each of said flanges internally receiving a tube and having its inner peripheral surface in resiliently flexed sealing engagement with the outer peripheral surface of its associated tube, each of said baille plates being in sealing engagement with the inner surface of said shell along a substantial portion of its outer periphery by reason of an outer radial flange integral therewith which is inclined axially relative to the longitudinal axis of said shell, said outer flange being in flexed resilient sealing engagement with said shell, and second fluid conduit means associated with said shell for communication thereinto for fluid contact with said baffle plates and the outer surfaces of said tubes.

2; A heat exchange unit having an outer elongated shell a plurality of apertures extending therethrough each bef ing defined by a circumferentially continuous liange extending axially with respect to said tubes, said anges being closely spaced to impart rigidity to the main portion of their associated baie plates, each of said anges being inwardly directed outwardly of its associated baiile plate, the smallest inner diameter thereof being less than the outer diameter of a tube received therethrough thereby placing said anges in flexed resilient sealing engagement with the outer periphery of said tubes, each of said baffle plates being in sealing engagement with the inner sur face of said shell along a substantial portion of its outer periphery by reason of an outer radial ange integral therewith which is inclined axially relative to the longitudinal axis of said shell, said outer flange being in flexed resilient sealing engagement with said shell, and second fluid conduit means associated with said shell for communication thereinto for fluid contact with said baie plates and the outer surfaces of said tubes.

3. A heat exchange unit having an outer elongated shell provided with header plates having first uid conduit means associated therewith, a plurality of tubes within said shell and extending longitudinally thereof with their ends sealed within apertures in said header plates, said tubes being in communication with said irst conduit means, a plurality of spaced baiie plates of lightweight resilient metallic material mounted on said tubes within said shell, each bae plate having a thickness on the order li of 0.01 to 0.03 of an inch, each of said baffle plates including a plurality of apertures extending therethrough each being defined by a circumferentially continuous flange extending axially with respect to said tubes, the majority of said apertures being spaced from one another with respect to their centers at approximately 0.5 inch to impart rigidity to said batiie plates, each of said anges being inwardly directed outwardly of its associated baliie plate, the smallest inner diameter thereof being less than the' outer diameter of a tube received therethrough thereby placing said anges in flexed resilient sealing engagement with the outer periphery of said tubes, each of said batiie plates being in sealing engagement with the inner surface of said shell along a substantial portion of its outer periphery by reason of an outer radial flange integral therewith which is inclined axially relative to the longitudinal axis of said shell, said outer flange being in exed resilient sealing engagement with said shell, and second uid conduit means associated with said shell for communication thereinto for fluid contact with said baffle plates and the outer surfaces of said tubes.

References Cited in the tile of this patent UNITED STATES PATENTS 1,293,663 Averill Feb. 11, 1919 1,304,496 MacLachlen May 20, 1919 1,787,942 Kalloch n Ian. 6, 1931 1,865,051 Trane June 28, 1932 1,983,549 Krackowizer Dec. 11, 1934 2,183,160 Coulter et al Dec. 12, 1939 2,256,993 Van Vleet Sept. 23, 1941 2,283,391 Siefken May 19, 1942 2,469,316 Shaw May 3, 1949 2,577,832 Weiks Dec. 11, 1951 2,595,822 Uggerby May 6, 1952 

